Performance requirements of the market for an LCD panel are toward characteristics of high contrast ratio, no gray scale inversion, little color shift, high luminance, high chroma, high color saturation, high response, wide viewing angle, and so on. At present, technical solutions that are capable of achieving the demand of the wide viewing angle have adding a wide viewing film to twist nematic (TN) liquid crystals, an in-plane switching (IPS) LCD panel, a fringe field switching (FFS) LCD panel, a multi-domain vertically alignment (MVA) LCD panel, and so on.
The MVA LCD panel herein has a most remarkable effect of the wide viewing angle. However, title directions of the LC molecules, which are around alignment protrusions and alignment slits of the MVA LCD panel, are often uncertain, resulting in a light leakage situation for causing a contrast of a display of the LCD panel to decrease. If a light shield layer corresponding to the alignment protrusions or the alignment slits is disposed for shielding the leaked light, an aperture ratio of the display will be limited. Thus, display luminance of the LCD panel still can not be raised.
As a result, a polymer-stabilized alignment (PSA) method, which forms multiple aligning directions, has been proposed to improve the drawback of the poor contrast of the MVA LCD panel.
The PSA method adopts reactive monomers to blend into an LC layer firstly and applies a predetermined voltage thereto. The LC layer is irradiated by an ultraviolet (UV) light under the voltage. The reactive monomers are then polymerized and cured to form a polymer layer simultaneously on opposite sides of substrates beside the LC layer.
The aligning voltage applying device is widely used in an UV exposure apparatus and an inspector after the alignment process. The aligning voltage is applied to the corresponding LC layer through probe pins of the aligning voltage applying device and pads of the LCD substrate. As shown in FIG. 1 and FIG. 2, FIG. 1 is a top view schematically illustrating an aligning voltage applying device in the prior art, and FIG. 2 is a cross-sectional view along A-A′ in FIG. 1. The LCD substrate is designated at 10, and the aligning voltage applying device is designated at 20. The aligning voltage applying device 20 is disposed around four edges of the LCD substrate 10, in which a base is designated at 21, and the probe pins that are disposed on the base 21 is designated at 22. The base 21 is raised through a motor, so that the probe pin 22 contact pads (not shown) which are disposed on the edges of the LCD substrate 10 for applying the aligning voltage. However, the edges of the LCD substrate 10 are easily deformed and bent (as shown at B area in FIG. 2) due to fabrication, thus resulting a contact miss between the probe pins 22 and the pads, such that the alignment of the LCD substrate 10 after exposing the UV light is poor.
At present, this problem can be avoided just by fine tuning the probe pin 22 to elevate manually, but the probe pins 22 may contact the pads too heavily if the probe pins 22 are excessively elevated. It may cause damage to the probe pins 22 and the LCD substrate 10.
Therefore, there is a significant need to provide an aligning voltage applying device and a method for applying aligning voltage to solve the problems existing in the prior art.